Vehicle body air circulating and conditioning apparatus



3 Sheets-Sheet l Invzn'rcm. N.H. CHR STMAN,

J. N. H. CHRISTMAN Filed Aug. 1, 1936 ll l|||||| .ll

May 16, 1939.

v-l/um ATTORNEYS y 16, 1939! v .1. N. H. CHRISTMAN 2,153,741

VEHICLE BODY AIR C'IRCULATING AND CONDITIONING APPARATUS Filed Aug. 1, 1936 3 Sheets-Sheet 2 INVENTOR. J'UHN N.H.CHms1-MAN.

ATTORNEYS y 1 3 J. N. H. CHRISTI-KN VEHICLE BODY AIR CIRCULATING AND CONDITIONING APPARATUS Filed Aug. 1, 1936 3 Sheets-Sheet 3 INVENTOR. Jo H N N. H. CHRISTMfl/V.

y Q QQM/M I ATTORNEY.

Patented May 16 1939 UNITED STATES PATENT OFFICE VEHICLE BODY AIR CIRCULATING AND CONDITIONING APPARATUS Application August 1, 1936, Serial No. 93,771

4 Claims.

This invention relates to vehicle body air circulating and conditioning apparatus and more particularly to a correlation of heat exchangers I and air circulating means by which a more efiec- I tive flow of air through the exchangers and into the body is obtained.

. One. of the principal objects of the present invention is to provide an air conditioning unit comprising a plurality of heat exchangers 9 through which air is passed in a manner such that the air streams of the exchangers are in mutually inducive relationship to each other with resultant economy in the power necessary I for forcing the air through the exchangers.

A correlative object is to automatically maintain a predetermined balance of the air flowing through the respective exchangers.

A more specific object is to provide controls for the exchangers by which the exchangers may 20 be rendered active or idle readily so that air may be supplied into the body uninfluenced by the exchangers when desired. as a result of which the usual expensive repeated installations and removals of the exchangers are rendered unnecessary, yet the exchangers are readily avail-able for instant use at all times.

Another specific object is to provide an exhaust heater and circulating system in which air may be forced and discharged through the heater to 3 the outside air so as to prevent deterioration of the heater due to overheating during periods when it is not used for heating the body.

Other objects and advantages will become apparent from the following specification wherein 5' reference is made to the drawings in which:

Fig. l is a top plan view of a motor coach with the present invention installed therein, part of the coach being shown in section for clearness in illustration;

Fig. 2 is a side elevation of the coach and present invention illustrated in Fig. 1;

Fig. 3 is an enlarged top plan view of the air conditioning apparatus and the air circulating system therefor and is taken on the plane indicated by the line 3--3 in Fig. 4';

Fig. 4 is a vertical sectional view taken on a plane indicated by the line 4-4 in Fig. 3; and

Fig. 5 is a flow diagram of the present invention illustrating the manner in which heat is supplied to the exchangers and the air is introduced into and circulated therethrough into the coach body.

Referring first to Figs. 1 and 2, there is illustrated a motor coach having a body, designated generally as l, at the front of which is located an internal combustion engine 2 provided with the usual radiator 3 and a rearwardly extending exhaust pipe 4. Air is supplied into the body through an air inlet conduit 5, having an inlet opening it at the top front wall of the body. In order to exhaust air from the body, suitable ducts l, protected by louvres t, are provided near the top front wall of the body. Air is supplied into the body through the opening 6 consequent upon forward motion of the vehicle. Air is exhausted from the body through the ducts l due to the low air pressure zone created along the top wall of the body by the relatively rearwardly onrushing air occasioned by forward motion of the body.

In order to condition the air prior to its introduction into the body, the conduit 5 is connected to theinlet side of a suitable blower Ill driven by a motor lilo. The blower l0 discharges into a box or header, designated generally at H. from which it passes through the heat exchang ers of the present invention and thereafter is recollected and discharged through a distribution duct l2 extending along one side of the body at the floor level. The duct it, in turn, is provided with a number of discharge ports It so that the air admitted into the body is uniformly distributed initially therealong and flows upwardly forwardly as indicated by the arrows in Figs. 1 and 2, to the discharge ducts l, thus completing the circulatory cycle.

As better illustrated in Figs. 3 and 4, there is provided in the header ll a heat exchanger l5 which, for purposes of illustration, is shown as a water heating core. The exchanger It is provided with an inlet conduit l6 and a discharge conduit H which connect the exchanger with the water cooling system of the engine.

The blower lll discharges into a compartment Ill in the header H, which compartment is spaced rearwardly from the exchanger I5. In its forward wall, the compartment it has a discharge opening l9 facing toward the exchanger l5, the opening l9 being somewhat smaller in area than the projected area of the exchanger l5. Leading from the opening it to the rear face of the exchanger is a flared expansion nozzle til, the nozzle 20 preferably being in sealed relation with the compartment 3 and with the heat exchanger l5. With this arrangement, air supplied by the blower l0 into the compartment 3 flows forwardly through the nozzle 2!] and then through the exchanger l5 from which it passes through a suitable duct 2| in the header ll into the distribution duct I! of the body.

Since abrupt angles in the duct 2i 'wouldtend to create eddy currents and back pressure and thus reduce the air flow, all changes in the angular direction thereof of the duct l2 are relieved by suitable rounded wall portions or baiiles, such as indicated at I21: and Ma.

In addition to the opening ill a smaller opening 22 is provided in the side wall of the compartment l8 so that part of the air entering the compartment is delivered through the opening 22. Connected with the opening 22 is a supply conduit 23 which, as illustrated in Fig. 1, leads to a suitable exhaust heater 24. Leading from the exhaust heater 24 is a return conduit 25 which re-enters the header II and terminates in a discharge nozzle 26. The nozzle 26 extends through the compartment IS in coaxial relation to the nozzle 20 and is tapered from the end adjacent its connection with the return conduit 25 toward the opposite end. The discharge end 26a of the nozzle 26 extends slightly into the inlet end of the nozzle 20 and is of smaller diameter than the nozzle 20 so as to define with the opening IS a restricted annular air induction passage 21.

Thus when air under pressure is supplied into the compartment H! by the blower In, part of this air flows directly through the annular passage 21 into the nozzle 20 at relatively high velocity due to the restricted area of the passage 21. This high velocity air stream creates a subatmospheric pressure around the discharge end 26a of the nozzle 26 which sub-atmospheric pressure is sufiicient to induce a comparatively high volume of flow of air through the nozzle 26. At the same time, losses by eddy currents are reduced in the nozzle 20. This induction effect of itself, would create a flow of air through the exhaust heater 24 and conduit 25 if air at normal atmospheric pressure were admitted to the exhaust heater 24. Since, however, the exhaust heater 24 also is-connected through the opening 22 and conduit 23 with the compartment l8, part of the air from the blower I is forced through the exhaust heater 24. Thus the air passing through the exhaust heater in which the resistance to flow may be considerable is caused to pass therethrough not only by superatmospheric pressure at the inlet end of the exhaust heater but also by sub-atmospheric pressure at the discharge thereof. As a result of the greater efliciency of flow obtained by this arrangement, the power required to drive the blower I0 is greatly reduced.

Since the nozzle 26 is contracted in cross sectional area in the direction of flow with resultant high velocity delivery, the nozzle 20 is in flow inducing relation to the nozzle 26. Due to this inductive relationship and the fact that both exchangers are connected to a common source of air, a balanced relation between the volumes of air passing through the respective exchangers is obtained.

As illustrated, the header H is preferably arranged below the fioor level of the vehicle and suitable insulation is used where desirable to reduce radiation losses. 2 As heretofore described, air is supplied to the inlet of the blower l0 through the conduit 5. The air thus supplied is delivered under considerable pressure to the blower when the vehicle is moving forwardly so that the power requirements are further reduced.

In order that both the water heat exchanger l and the exhaust heat exchanger 24 may be shut off readily, insofar as the air supplied in the body is concerned, so that the air circulation system can be utilized independently of and without dismantling the air conditioning apparatus, a suitable cut-off valve 28 is provided in the supply conduit l6 leading to the water heat exchanger I5. The valve 28 is preferably arranged in a convenient location for access by the driver of the vehicle so that it can be closed to block the flow of water to the exchanger I5 from the engine cooling system instantly when desired. A cut-off valve 29 is also provided between the discharge side of the exhaust heat exchanger 24 and the nozzle 26 for blocking the flow of air into the body, the valve 29 being arranged with suitable vents which, when the valve is in position to block the flow of air into the body, permit a relatively small flow of air from the exhaust heat exchanger into the outside atmosphere. Consequently, during summer operation, a small amount of air is continuously forced through the exhaust heat exchanger 24 and discharged into the outside atmosphere so that danger of overheating of the exhaust heat exchanger is eliminated.

In summarizing briefly the circulation of air and heating media, reference is made to the flow diagram of Fig. 5. As there illustrated, water leaving the block of the engine 2 is lead from the discharge side of the usual engine water circulating pump through the conduit l6 into the heat exchanger and, upon passing therethrough, is returned through the return conduit IT to the engine water cooling system, preferably at the hose connection between the radiator 3 and base of the engine block. By means of the valve 28, the heat exchanger l5 can be entirely disassociated from the engine cooling system at any time.

Heat is supplied from the engine through the exhaust manifold 4 to the exhaust heat exchanger 24. Air is forced into the conduit 5 through the inlet 6 due to the forward motion of the vehicle and passes into and through the blower ID by which it is forced into the compartment [8. This air passes from the compartment l8, part directly through the nozzle to the water exchanger l5 and part through the conduit 23 into and through the exhaust heat exchanger 24 and thence therefrom through the conduit 25 into the nozzle 26. Thus as thepressure increases in the compartment N3, the volumes of air passing through the water heat exchanger l5 and the exhaust heat exchanger 24 are increased concurrently but maintain a fairly close proportional relationship or balance. Due to the restricted annular passage 21, the flow of air through the exhaust heater 24' is augmented by the induction effect, at the discharge 26a of the nozzle 26. Correspondingly, air from the nozzle 26 induces a flow through the passage 21.

Since the nozzle 20 expands in the direction of flow, the admixture of the relatively cool air and the air issuing from the nozzle 26 does not tend to reduce the flow as the expansion of the relatively warmer mixture is permitted.

If for a temporary warm period it is desired to disassociate the exhaust heater from the air circulating system, it is only necessary to close the valve 29 which, when closed, exposes a small bleeder vent 30 in the conduit 25. The vent 30 is normally blocked by the valve 29 when the valve is in open condition but, when the vent is exposed by closing the valve 29, the vent permits a filtration of air through the exhaust heat exliii lationship to the conduit leading to the otherv exchanger.

2. In a vehicle body air circulating and conditioning apparatus, a water heat exchanger, an exhaust heat exchanger, a header connected to a source of air under pressure, a discharge nozzle connected with the header and leading to the water heat exchanger, air conduit means leading from the header to the exhaust heat exchanger,

3. In a vehicle body air circulating and condi-v tioning apparatus, a pair of heat exchangers, means for supplying a source of air under pressure, a discharge nozzle for said air and leading to one of the exchangers, an air conduit for air from said source and leading to the other exchanger, discharge conduit means leading from the last mentioned exchanger to a discharge nozzle, said last discharge nozzle having its discharge end adjacent the inlet end of the first nozzle and defining therewith a restricted passage, and one of said nozzles being contracted in the direction of flow of air therethrough, whereby said nozzles are in flow inducing relation to each other.

4. In a vehicle body air circulating and conditioning apparatus, a water heat exchanger, an exhaust heat exchanger, a header connected to a source of air under pressure, a discharge nozzle connected with the header and leading therefrom tothe water heat exchanger, an air conduit leading from the header to the exhaust heat exchanger, a discharge conduit leading from the exhaust heat exchanger to a discharge nozzle, said last discharge nozzle being coaxial with the first nozzle and having its discharge end at the inlet end of the first nozzle and in inwardly spaced relation to the walls thereof for defining therewith a restricted passage surrounding said last nozzle, whereby said nozzles are in flow inducing relation to each other.

JOHN N. H. CHRISTMAN. 5 

